1. Field of the Invention
This invention is related to a latex composition containing an agent to aid the coalescence of the emulsified or suspended resin or elastomer particles necessary for the formation of a continuous film.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Latex compositions comprising an emulsion or suspension of polymer particles such as resins or elastomers in an aqueous medium, are widely used in various applications, e.g., coatings such as paints and clear coatings, adhesives, and dipping and impregnating compositions. For all or most of these applications, the latex must be capable of forming a strong, adherent and continuous film at a reasonably low temperature. In order to achieve these properties, it is common to incorporate into the latex a coalescing agent which is usually a partial solvent for the polymer, i.e., the resin or elastomer, particles serving as the film forming constituent of the composition. The solvent action of the coalescing agent on the emulsified or suspended particles allows them to coalesce into a strong, adherent and continuous film at a temperature sufficiently low to maintain the utility of the composition for its contemplated applications, e.g., exterior paints which are intended to be suitable for use in cold weather, as well as interior paints which are generally exposed to more moderate temperatures.
The following references may be considered relevant to the invention claimed herein.
U.S. Pat. No. 4,076,727 issued Feb. 28, 1978 to Zey et al. and U.S. Pat. No. 4,207,155 issued Jun. 10, 1980 to Martin et al. disclose the production of monohydroxy monocyclic acetals by reacting a trihydroxy alcohol such as trimethylolpropane or trimethylolethane with an aldehyde such as formaldehyde. The monohydroxy monocyclic acetals are stated to be useful in the synthesis of acrylate and methacrylate esters which are suitable as reactive monomers in the preparation of polymers for coating compositions, particularly those which are UV curable.
U.S. Pat. No. 4,435,534 issued Mar. 6, 1984 to Jones et al., discloses latex coating compositions containing as a coalescent an alkoxyethyl benzoate or similar ester in which a ring hydrogen atom is substituted with an alkyl group, e.g., a toluate.
U.S. Pat. No. 4,489,188, issued Dec. 18, 1984 to Jones et al., has a disclosure similar to that of U.S. Pat. No. 4,435,534 discussed previously except that it also discloses alkoxy 1-methylethyl benzoates and alkyl ring-substituted benzoates as coalescents.
U.S. Pat. No. 4,525,512, issued Jun. 25, 1985 to Hudson, discloses the use of esters of alkyl diglycol ethers with mono- and dicarboxylic acids as coalescing agents in polymer latices employed in paint formulations.
U.S. Pat. No. 4,649,170, issued Mar. 10, 1987 to Reid, discloses a water-based all acrylic, underbody coating containing a coalescing agent such as ethylene glycol or ethylene glycol mono butyl ether.
U.S. Pat. No. 4,876,368, issued Oct. 24, 1989 to Broussard et al., discloses a process for the production of a monohydroxy monocyclic acetal, e.g., trimethylolpropane cyclic formal by reaction of a trihydroxy alcohol, e.g., trimethylolpropane, and an aldehyde, e.g., formaldehyde, including the step of subjecting at least part of a heavier condensation product than the desired cyclic acetal to acetal formation conditions.
U.S. Pat. No. 5,186,744, issued Feb. 16, 1993 to Bodwell et al., discloses, as coalescing agents in water-based protective coating compositions, propoxylated propylene glycol tert. butyl ether (propoxylated PTB) and mixtures of propoxylated PTB with an organic solvent.
U.S. Pat. No. 5,236,987, issued Aug. 17, 1993 to Arendt, discloses the use of benzoate esters containing 8 to 12 carbon atoms in their alcohol moiety, as coalescing agents in latex paint formulations.